Method and apparatus for determining the orientation of eccentric bushings

ABSTRACT

A method of replacing eccentric bushings installed on the gangheads of machine tools for adjusting a machining operation. The machine tools, which are used to machine or otherwise process parts, utilize the eccentric bushings for applying fine adjustments to the machining by adjusting the location of the machining operation in a plane using the orientation and amount of eccentricity of the bushing. Also the apparatuses provided for supporting this method.

BACKGROUND

This application relates generally to a method of replacing bushings ona machine, and more specifically, this application relates to thereplacement of eccentric bushings on the gangheads of machine tools thatutilize the eccentric bushings for applying fine adjustments to thetools of the machine tool for processing parts or other products.

Eccentric bushings are sometimes utilized inside CNC machine tools, suchas in their docking posts, in situations where the tools cannot befinely adjusted in a Cartesian two-dimensional manner (i.e., adjusted ina vertical-y and horizontal-x direction for a tool machining in the x, yplane), or in situations where additional adjustments to the machiningoperation are desirable. However, over time, the bushings can wear orthe machine tools otherwise become out-of-adjustment, in which caseadjustments to the machining operation are desirable. Such adjustmentsmay be done by replacing the eccentric bushings, in some circumstances.

Conventional approaches for replacing eccentric bushings have involvedcomplex manual calculations by hand that can take a long time toaccomplish and thus are inefficient, and because of the complex manualcalculations, errors can be introduced.

Hence, a new approach to adjusting or replacing such eccentric bushingsthat overcomes one or more of these problems is desirable.

SUMMARY

Provided are a plurality of example embodiments, including, but notlimited to, a method of installing a bushing in a device, comprising thesteps of: determining a desired effect of a bushing on the device;automatically determining, using a computer executing a softwareapplication, a desired parameter of the bushing based on the desiredeffect; automatically determining, using the computer executing thesoftware application, a desired installation orientation of the bushingbased on the desired effect; and installing the bushing in the deviceaccording to the installation orientation, wherein the devicesubstantially exhibits the desired effect.

Also provided is a method of replacing an eccentric bushing in a device,comprising the steps of: determining an installation orientation of acurrent bushing installed in the device; removing the current bushingfrom the device; determining at least one characteristic of the currentbushing; calculating at least one desired characteristic of areplacement bushing; selecting the replacement bushing based on at leastone of the at least one desired characteristic of the replacementbushing; determining an installation orientation of the replacementbushing at least partially based on at least one characteristic of thecurrent bushing; and installing the replacement bushing in the deviceaccording to the determined installation orientation of the replacementbushing.

Still further provided is a method of replacing an eccentric bushing ina device, comprising the steps of: determining an installationorientation of a current bushing installed in the device; providing onmark on the device indicating the current installation orientation;providing a mark on the current bushing indicating the currentinstallation orientation; removing the current bushing from the device;determining a value and location of a high point of eccentricity of thecurrent bushing; providing a mark on the current bushing indicating theposition of the high point of eccentricity of the current bushing; usinga position indicating device for determining a relative orientationdistance between the mark indicating the high point of eccentricity ofthe current bushing relative to the mark indicating the currentinstallation orientation of the current bushing; calculating, using acomputer program executing on a computer, a position and desired valueof a high point of eccentricity of a replacement bushing based oncriteria including: the value of the high point of eccentricity of thecurrent bushing, the relative orientation distance of the currentbushing, and desired adjustments to be made to the device; providing thereplacement bushing that best matches the desired value of the highpoint of eccentricity of the replacement bushing; locating and providinga mark of the position of the high point of eccentricity of thereplacement bushing; using the position indicating device fordetermining an installation orientation for the replacement bushingbased on the mark of the position of the high point of eccentricity ofthe replacement bushing and also based on the calculated position of thehigh point of eccentricity; providing a mark on the replacement bushingindicating the installation orientation; and installing the replacementbushing in the device according to the mark on the replacement bushingindicating the installation orientation and according to the mark on thedevice indicating the current installation orientation, whereby thedesired adjustments are substantially made to the device.

Also provided are additional example embodiments, some, but not all ofwhich, are described hereinbelow in more detail.

BRIEF DESCRIPTION OF THE DRAWINGS

The features and advantages of the example embodiments described hereinwill become apparent to those skilled in the art to which thisdisclosure relates upon reading the following description, withreference to the accompanying drawings, in which:

FIG. 1 is a front view of an example ganghead that has a docking postutilizing an eccentric bushing;

FIG. 2 is a close-up view of the eccentric bushing installed in theexample ganghead of FIG. 1 with the docking post removed;

FIG. 3 is a view of a level insert installed in eccentric bushing ofFIG. 2;

FIG. 4 is a view of the eccentric bushing of FIG. 2 marked with a 12:00position;

FIG. 5 is a view of the eccentric bushing of FIG. 2 being measured by acaliper with its highpoint marked;

FIG. 6 is a view of an example position indicating device being usedwith the bushing of FIG. 5 to determine the position of its highpoint;

FIG. 7 is a screen shot of an example user interface for an exampleapplication for determining a desired bushing eccentricity;

FIG. 8 is the screen shot of FIG. 7 showing example data andcalculations;

FIG. 9 is a view of a replacement eccentric bushing being measured bythe caliper with its highpoint marked;

FIG. 10 is a view of the position indicating device being used with thereplacement bushing of FIG. 9 to determine its 12:00 position; and

FIG. 11 is a close-up view of the replacement bushing installed in theganghead to replace the eccentric bushing shown in FIG. 2.

DETAILED DESCRIPTION OF THE EXAMPLE EMBODIMENTS

FIG. 1 shows an example ganghead 1 of a CNC machine tool, where toolholders 3 and 5 are used to hold tools (such as drill bits or ream bits,for example, not shown) to machine a part being carried by a pallet, forexample. Docking post 10 is provided to match the pallet (not shown)that is a carrier of the part to be machined, with the part being heldby the pallet in a position to be machined. More than one such dockingpost may be provided on some gangheads. Generally, the machine tool canbe adjusted in the x-y plane (or x-z or y-z plane) by providingeccentric bushings in the docking post. The eccentric bushings operateto finely move the position of the where tool holders 3, 5 (and therebymove the position of the tools) with respect to the part to be machined(when the pallet holding the part is mated to the ganghead) in a desireddirection in the x-y plane, to perform one or more machine operations onthe part. Hence, the location of machine operations on the part in thedesired plane can be finely controlled through the use of eccentricbushing(s) in the docking post(s) 10, even when the CNC tool cannot beprogrammed to do so.

FIG. 2 shows a close-up of the ganghead 1 with the docking post 10removed from its mount 11. Bushing 100 is provided in the docking postmount 11 at hole 13. Generally, as discussed above, it is desirable thatthe eccentric bushing 100 be eccentric in shape (i.e., not be perfectlyround, but have a high point that is out-of-round) to provide a desiredfine adjustment of the tooling operation that the tools of the ganghead1 perform on the part, with respect to the x-y plane. However, theeccentric bushing 100 may go out of adjustment, or over time additionaladjustment of the machining of the part may be desired (such as due tochanges in the machine tool and/or its components over time), in whichcase it may be desirable to replace the bushing 100 (and potentiallyother bushings as well) to obtain the desired fine adjustment of themachining process.

In order to replace the eccentric bushing 100, it is desirable todetermine its current position and amount of eccentricity, and todetermine how best to install a new eccentric bushing to regain thedesired adjustment of the ganghead. In order to do so, the currentposition of the bushing must be determined. However, the ganghead itselfshould be leveled prior to this operation.

Referring to FIG. 3, a level 111 mounted on a level insert 110 is usedto determine an orientation of the ganghead, in this case the 12:00position of the mount, by installing the level insert 110 in the centerof the bushing 100, which is covered by the level insert and thus notseen in FIG. 3. Using an indication 112 located on the level insert 110which indicates the 12:00 position, a mark 113 is provided on the mount11 using paint or a marker at the 12:00 position, so that the mark 113matches the location of the indication 112. Preferably, the mark 113should be in color chosen to indicate its purpose, and in this examplecase, it is chosen to be a red mark to signify that it represents the12:00 position. This mark 113 now provides an orientation baseline forthe replacement process.

Referring to FIG. 4, the level insert 110 with the level 111 is removed,and the bushing 100 is marked at the 12:00 position 115 to match the12:00 position of the mark 113 previously provided on the mount 11. Itis preferable that this mark be done using the same color as thecorresponding mark on the mount 11, and thus in this example it ismarked in red to indicate that it represents the 12:00 position. Thebushing 100 is thereby marked to show its installation orientation inthe ganghead.

The eccentric bushing 100 is then removed from the mount 11 to bemeasured and replaced. In some cases, the removal of this bushing 100may require the use of a tool, as the bushing may be snug in its fit.

FIG. 5 shows the eccentric bushing 100 being measured using a caliper30. The bushing 100 is rotated in the caliper as its thickness ismonitored in order to examine its amount of eccentricity by finding thevalue and location of its high point (in this case it is found to havean eccentric high point of 0.060 mm). Mark 115 can be seen on thebushing, and a new mark 120 is put on the bushing at the high point asfound by using the caliper 30. This mark 120 should be in a differentcolor than that used for mark 115 to properly differentiate the mark asindicating the high point on the bushing. In this example, the mark 120is done in yellow.

As shown in FIG. 6, to determine the location of the high point 120 withrespect to the 12:00 position (and thus determine the relative distancebetween them), the bushing 100 is then placed in a position indicatingdevice 60 which has a dial 61 that, in this example, is divided intoindications of 12 hours and fractions thereof. Of course, other types ofindications not based on time (clocks) could also be used. The red 12:00mark 115 is placed at the 12:00 position on the device 60 dial 61, andthe position of the yellow mark 120 can be read on the dial 61. In thisexample, the mark is shown at the 2:30 position. Thus is it determinedwhere the high point of the eccentric bushing 100 is located withrespect to the 12:00 position, giving a relative position between them(in this example, the distance is measured in “hours”).

Now it is desired to determine what the desired dimensions of thereplacement bushing should be. An example software application runningon a computer is used for determining the desired replacement bushingdimensions is utilized to determine the desired parameters of thereplacement bushing. Any commercially available computer can be used,such as a personal computer running MS Windows, or a server, forexample, provided with a GUI interface for user interaction. Portablecomputers could also be utilized. The software application can bedeveloped using any commercially available programming language, such asC or Java, or any other programming language, and may be web-based. Thesoftware application is programmed such that, based on the setup of themachine tool, ganghead, the tool holders, and the location of the partto be machined, the desired parameters (characteristics) of replacementeccentric bushing, e.g., their high-point value and installationorientation, can be determined based on desired impacts to the machiningoperation, and based on the parameters of the current bushing, that areinput to the software application by the user.

FIG. 7 shows a screen shot of an example user interface 50 for anexample software application that can be used for the exampleembodiment. Various fields will be populated at various stages of theprocess. Instructions 51 describing proper use of the softwareapplication are provided to the user via this user interface 50. Thisexample software application can be used for various differentprocesses, so the user chooses the current desired process using a dropdown menu 59 (choosing from options such as “docking post” or“individual spindle”, for example).

The user interface 50 has a current part location field 54 for enteringa desired adjustment of the ganghead tools (which will result inmachining the part at the desired location, as compared to the previoussetup using the original eccentric bushing which was not at the desiredlocation); a CMM reference sheet field 53 where data can be directlyentered, if desired; a time chart 52 indicating the inner diameter ofthe type of bushing being replaced; a current bushing information field55 for entering information about the current bushing 100 that is beingreplaced; a current bushing ganghead effect field 56 for showing theeffect the current bushing has on the ganghead, a replacement bushingganghead effect field 57 for showing the effect that the desiredreplacement bushing will have on the ganghead placement with respect tomachining the part; and a replacement bushing desired dimensions field58 for indicating the desired parameters of the replacement bushing.

Referring now to FIG. 8, the user enters the amount and direction thatthe current part is away from nominal (an error amount) by action of thecurrent bushing by entering the data into the current part locationfield 54′. For this example, the variance from desired location is 0.035mm vertical and 0.040 mm horizontal (of course, instead of entering anerror amount, absolute desired location information could be used, orsome other indication of the desired changes, in different exampleapplications). The user also enters the information determined about thecurrent bushing 100 in the current bushing information field 55′. Thisincludes the high point measurement and its location. For this example,the high point of the current bushing was found to be 0.060 mm at the4:30 position.

The software application then determines a desired size and eccentricityangle of the replacement bushing displayed in the replacement bushingdesired dimensions field 58′. In this case, the software applicationdetermines that a replacement bushing having a 0.113 mm high point beingused at an installation orientation of 4:26 is desirable. The softwareapplication takes into account the characteristics of the machine tool(the location of the tools and the part being machined, and the locationof the bushings and their impact on the machining process), in order toperform these calculations. Thus, the software application must beadapted to include parameters for the particular machine tool beingmodified.

A replacement bushing 200 is chosen, such as by trial and error inmeasuring potentially acceptable bushings, or by selecting frompre-measured, previously sorted bushings. It is desired that areplacement bushing be selected that is as close as possible to thedesired dimensions determined by the application (i.e., an eccentrichigh point of 0.113 mm). The thus selected replacement bushing is placedin the caliper 30 as shown in FIG. 9 and the high point of the bushingis determined using the caliper, with the high point being marked inyellow using indication 220. Then, the replacement bushing 200 is placedin the position indicating device 60 as shown in FIG. 10 with the yellowhigh point mark 220 placed at the position determined by the softwareapplication as displayed on the user interface 50, in this case atapproximately the 4:26 position as shown in the figure. Then, the 12:00position 215 is marked in red on the new bushing 200 for indicating thedesired installation orientation of the replacement bushing 200.

If desired, the software application can be adapted to show the impactof the actual values of the replacement eccentric bushing on the machinetool, if those values vary from the desired values.

Properly marked, the replacement bushing 200 is now ready to beinstalled on the mount 11 of the ganghead 1 as shown in FIG. 11, withthe bushing installed with the 12:00 mark 215 matching the 12:00 mark113 at the hole 13 of the mount 11. This results in the replacementbushing 200 being installed in the desired orientation. The docking post10 can then be installed on the mount 11 to return the ganghead 1 to thestate found in FIG. 1, but with the machine tool now better able toposition the machining tools at the desired machining locations.

The system and procedures identified herein can also be used for otherapplications where the positioning of a part based on some criteria mustbe determined and/or adjusted, beyond use in machining operations, butanywhere fine adjustments or replacement of finely differentiated partsis desirable.

Many other example embodiments can be provided through variouscombinations of the above described features. Although the embodimentsdescribed hereinabove use specific examples and alternatives, it will beunderstood by those skilled in the art that various additionalalternatives may be used and equivalents may be substituted for elementsand/or steps described herein, without necessarily deviating from theintended scope of the application. Modifications may be necessary toadapt the embodiments to a particular situation or to particular needswithout departing from the intended scope of the application. It isintended that the application not be limited to the particular exampleimplementations and example embodiments described herein, but that theclaims be given their broadest reasonable interpretation to cover allnovel and non-obvious embodiments, literal or equivalent, disclosed ornot, covered thereby.

What is claimed is:
 1. A method of installing a bushing in a device,comprising the steps of: determining a desired effect of a bushing onthe device; automatically determining, using a computer executing asoftware application, a desired parameter of the bushing based on thedesired effect; automatically determining, using the computer executingthe software application, a desired installation orientation of thebushing based on the desired effect; and installing the bushing in thedevice according to the installation orientation, wherein the devicesubstantially exhibits the desired effect.
 2. The method of claim 1,further comprising the steps of: determining a value of a high point ofeccentricity of a previous bushing installed in the device; and removingthe previous bushing from the device, wherein both of the steps ofautomatically determining are also based on the determined value of thehigh point of eccentricity of the previous bushing.
 3. The method ofclaim 2, further comprising the step of determining an installationorientation and a position of the high point of eccentricity of theprevious bushing, wherein both said automatically determining steps arealso based on the determined installation orientation and position ofthe high point of eccentricity of the previous bushing.
 4. The method ofclaim 3, wherein said device is a device for machining a part, andwherein the desired effect is based on a desired location for the deviceperforming machining on the part.
 5. The method of claim 4, wherein thedesired effect is also based on a location of the device performingmachining on the part with the previous bushing installed.
 6. The methodof claim 4, wherein the desired parameter includes a value of a highpoint of eccentricity of the bushing.
 7. The method of claim 1, whereinthe desired parameter includes a value of a high point of eccentricityof the bushing.
 8. The method of claim 1, wherein said device is adevice for machining a part, and wherein the desired effect is based ona desired location for the device performing machining on the part. 9.The method of claim 1, further comprising the step of, prior toinstalling the bushing in the device, marking the bushing to indicatethe desired installation orientation of the bushing.
 10. The method ofclaim 1, further comprising the step of selecting the bushing from aplurality of bushings based on the desired parameter.
 11. A method ofreplacing an eccentric bushing in a device, comprising the steps of:determining an installation orientation of a current bushing installedin the device; removing the current bushing from the device; determiningat least one characteristic of the current bushing; calculating at leastone desired characteristic of a replacement bushing; selecting thereplacement bushing based on the at least one desired characteristic ofthe replacement bushing; determining an installation orientation of thereplacement bushing at least partially based on the at least onecharacteristic of the current bushing; and installing the replacementbushing in the device according to the determined installationorientation of the replacement bushing.
 12. The method of claim 11,wherein said step of determining the installation orientation of thecurrent bushing includes the step of using a level to locate anorientation position on the device.
 13. The method of claim 12, whereinsaid step of determining the installation orientation of the currentbushing also includes the step of providing an installation mark on thecurrent bushing indicating its installation orientation with respect tothe located orientation position on the device.
 14. The method of claim13, wherein said step of determining at least one characteristic of thecurrent bushing includes the steps of: determining a position of a highpoint of eccentricity of the current bushing; and using a positionindicating device to measure a distance between the position of the highpoint of eccentricity of the current bushing relative to theinstallation mark on the current bushing, wherein said step ofdetermining the installation orientation of the replacement bushing isat least partially based on the measured distance.
 15. The method ofclaim 14, wherein said step of determining an installation orientationof the replacement bushing includes the steps of: determining a positionof a high point of eccentricity of the replacement bushing; andproviding a mark indicating the position of the high point ofeccentricity on the replacement bushing.
 16. The method of claim 15,further comprising the step of using the position indicating device tolocate an installation orientation of the replacement bushing relativeto the mark indicating the position of the high point of eccentricity onthe replacement bushing.
 17. The method of claim 16, further comprisingthe step of providing a mark indicating the installation orientation ofthe replacement bushing, wherein said mark indicating the installationorientation is used with the located orientation position on the devicefor installing the replacement bushing in the device.
 18. The method ofclaim 16, wherein a desired value for the high point of eccentricity onthe replacement bushing and the location of the installation orientationof the replacement bushing are determined based on a data output from acomputer program executing on a computer, wherein said data outputdetermined is based on a desired modification of the device and is alsobased on the installation orientation and the high point of eccentricityof the current bushing.
 19. The method of claim 11, wherein the step ofcalculating at least one characteristic of the replacement bushing isautomatically accomplished using a computer program executing on acomputer, such that the at least one characteristic is based on adesired modification of the device entered into a user interface to theprogram.
 20. A method of replacing an eccentric bushing in a device,comprising the steps of: determining an installation orientation of acurrent bushing installed in the device; providing a mark on the deviceindicating the current installation orientation; providing a mark on thecurrent bushing indicating the current installation orientation;removing the current bushing from the device; determining a value andlocation of a high point of eccentricity of the current bushing;providing a mark on the current bushing indicating the location of thehigh point of eccentricity of the current bushing; using a positionindicating device for determining a relative orientation distancebetween the mark indicating the high point of eccentricity of thecurrent bushing relative to the mark indicating the current installationorientation of the current bushing; calculating, using a computerprogram executing on a computer, a position and desired value of a highpoint of eccentricity of a replacement bushing based on criteriaincluding: the value of the high point of eccentricity of the currentbushing, the relative orientation distance of the current bushing, anddesired adjustments to be made to the device; providing the replacementbushing that best matches the calculated desired value of the high pointof eccentricity of the replacement bushing; locating and providing amark of a location of the high point of eccentricity of the replacementbushing; using the position indicating device for determining aninstallation orientation for the replacement bushing based on the markof the location of the high point of eccentricity of the replacementbushing and also based on the calculated position of the high point ofeccentricity; providing a mark on the replacement bushing indicating theinstallation orientation; and installing the replacement bushing in thedevice according to the mark on the replacement bushing indicating theinstallation orientation and according to the mark on the deviceindicating the current installation orientation, whereby the desiredadjustments are substantially made to the device.